The present invention relates to a device for eliminating sheet curl and more particularly for eliminating sheet curl from sheets emerging from a hot fixing station in a copying machine or any similar image processing machine.
It is well known, that in an electrophotographic copier the images to be reproduced are developed by means of particles of toner and are then transferred to a sheet of paper.
In order to fix the particles of toner to the paper, the sheets are passed through a fixing station, which works by heat and pressure, in which the particles of toner are softened and caused to penetrate into the paper, thereby fixing them stably to the paper.
As a result of the effect of the heat and pressure, tensions are created within the thickness of the paper and the sheets of paper tend to curl. Subsequently, when deposited in a delivery tray, the sheets may retain this curl and in some cases a sheet may roll up on itself.
Devices which attempt to overcome this problem are known which use stationary guides orientated in such a way as to bend the sheet in the opposite direction to that which it wishes naturally to adopt by curling. However, these devices fail to eliminate sheet curl altogether, and in fact with certain kinds of paper they can induce a curl in the opposite direction.